1. Field of the Invention
The present invention relates to a multiprocessor system and a control method thereof, and a computer-readable medium.
2. Description of the Related Art
In recent years, various information processing apparatuses are required to attain power savings. Hence, in order to reduce consumption power of apparatuses, those having a power saving mode in which consumption power is reduced compared to a normal mode in addition to the normal mode in which normal application processing is executed are increasing.
Various operations are made at a power saving mode. In general, operation voltages of some circuits and devices which configure an apparatus are lowered or a power supply to them is stopped, thus reducing consumption power. In this way, when some functions of the apparatus are not used or at a standby mode, the apparatus is set in the power saving mode, thereby effectively reducing consumption power.
As a technique for reducing consumption power at a power saving mode, a technique which executes a program allocated on an SRAM which requires a low operation voltage at a power saving mode to set other memories in the power saving state has been proposed (see Japanese Patent Laid-Open Nos. 2000-105639 and 2005-111715).
In these proposed techniques, programs and data allocated on an SDRAM are used and executed at the normal mode. At the power saving mode, the SDRAM is not accessed, and a program for the power saving mode is executed using only the program and data allocated on an SRAM that requires a lower operation voltage than the SDRAM. As a result, since the SDRAM can be set in a power saving state like a self refresh mode, consumption power at the power saving mode can be reduced.
On the other hand, in various embedded apparatuses and PCs, multiprocessor/multicore systems which incorporate a plurality of processors or a plurality of cores are increasing recently, and this trend is considered to accelerate in the future. In such multiprocessor/multicore systems as well, power savings are required.